package alg1_baseModel;
// 给出exR1(6)的返回值：
public class Test1_1_16 {
    public static void main(String[] args) {
        String result = exR1(6);
        System.out.println(result);
    }

    public static String exR1(int n){
        if (n <= 0) return "";
        return exR1(n - 3) + n + exR1(n - 2) + n;
    }
}
